World Library  
Flag as Inappropriate
Email this Article

Ammonium fluoride

Article Id: WHEBN0002087981
Reproduction Date:

Title: Ammonium fluoride  
Author: World Heritage Encyclopedia
Language: English
Subject: Tantalum, Ammonium chloride, Inorganic compounds by element, Ammonium bromide, Ammonium iodide, Tantalum pentoxide, Solubility table, List of UN numbers 2501 to 2600
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Ammonium fluoride

Ammonium fluoride
Identifiers
CAS number 12125-01-8 YesY
ChemSpider 23806 YesY
EC number 235-185-9
UN number 2505
RTECS number BQ6300000
Jmol-3D images Image 1
Properties
Molecular formula NH4F
Molar mass 37.037 g/mol
Appearance White crystalline solid
hygroscopic
Density 1.009 g/cm3
Melting point

100 °C (decomp)

Solubility in water 45.3 g/100 ml (25 °C)
Solubility slightly soluble in alcohol, insoluble in liquid ammonia
Structure
Crystal structure Wurtzite structure (hexagonal)
Hazards
MSDS ICSC 1223
EU Index 009-006-00-8
EU classification Toxic (T)
R-phrases R23/24/25
S-phrases (S1/2), S26, S45
NFPA 704
0
3
0
Flash point Non-flammable
Related compounds
Other anions Ammonium chloride
Ammonium bromide
Ammonium iodide
Other cations Sodium fluoride
Potassium fluoride
Related compounds Ammonium bifluoride
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Ammonium fluoride is the inorganic compound with the formula NH4F. It crystallizes as small colourless prisms, having a sharp saline taste, and is exceedingly soluble in water.

Crystal structure

Ammonium fluoride Adopts the wurtzite crystal structure, in which both the ammonium cations and the fluoride anions are stacked in ABABAB... layers, each being tetrahedrally surrounded by four of the other. There are NH...F hydrogen bonds between the anions and cations.[1] This structure is very similar to ice, and ammonium fluoride is the only substance which can form mixed crystals with water.[2]

Reactions

On passing hydrogen fluoride gas (in excess) through the salt, ammonium fluoride absorbs the gas to form the addition compound ammonium bifluoride. The reaction occurring is:

NH4F + HF → NH4HF2

It sublimes when heated—a property common among ammonium salts. In the sublimation, the salt decomposes to ammonia and hydrogen fluoride, and the two gases recombine to give ammonium fluoride, i.e. the reaction is reversible:

[NH4]F ↔ NH3 + HF

Uses

This substance is commonly called "commercial ammonium fluoride". The word "neutral" is sometimes added to "ammonium fluoride" to represent the neutral salt—[NH4]F vs. the "acid salt" (NH4HF2). The acid salt is usually used in preference to the neutral salt in the etching of glass and related silicates. This property is shared among all soluble fluorides. For this reason it cannot be handled in glass test tubes or apparatus during laboratory work.

It is also used for preserving wood, as a mothproofing agent, in printing and dying textiles, and as an antiseptic in breweries.[3]

References

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.